Governor-controlled compressor and the like



June 17; 1952 5, DALE 2,600,855

GOVERNOR-CbNTROLLED COMPRESSOR AND THE LIKE Filed March 18, 1946Patented June 17, 1952 UNITED STATES PATENT OFFICE GOVERNOR-CONTROLLED('JOIVIIRESSOR AND "THE LIKE" Josephs. Dale, nockfordpllle ApplicationMarch 18, 1946, Serial No."655, 087

e-fllaims. 1

This invention relates to a governor-controlled compressor :and similarstructures.- The invention-will be found applicable tomachines driven byprime movers and in which the load upon the prime mover increases to. amaximum then decreases.

In the operation-or compressors and the like, it is the ordinarypractice for the prime mover to operatesteadi'ly untilth pressure tankis at the desired pressure, at which time the compressor is cut offi"When the pressure again drops to a predetermined point, the-compressorcuts in again. Th constant cutting on and oil? of the compressor resultsin a: noisy and inefiicient operation. It-is highly desirable, inoperating an'air compressor, to have the prime mover slow down aspressure increases and to go faster as the pressure decreases.

An object oithe present invention is "to provide control mechanism whichwill slow down the operationof the prime mover as the load thereonincreases or as the pressur within the pressure tank 'increases,while,at the same time, allowing a-iaster speed of the prime mover whenpressure is low. Aifurth'er object is; to provide meansv w-herebywhenthe pressure within the pressure tank has reached its desired maximumand the compressor is in idling operation, the prime mover willnevertheless bemaintained at a relatively low speed. A furtherobjectistoprovidea governon the present invention; Fig. 2, a side view inelevation and'partlyin section of the governor and associated apparatusembodying my invention; Fig; 3, a--broken-side -view in elevation ofcombination apparatus embodying my invention; and Fig.4, an enlargeddetailed sectional view of the pressure line connection shown in Fig. 3.

In the illustration given, A designates a prime mover; B, a'compressordriven thereby; C, a pressure tank supplied withpressure fluid bycompressor B; I D, a governor driven by; the prime mover; andE; linkmechanism connecting the 2; overnor-and primermover-to effect apontrolor the prime mover.

The prime mover A may be of any suitable, type or construction. In; theparticular illustration, given, it consists of a motor equippedwith-athrottle valve H] which controls the intake of fuel into themanifold] 1. Since the type or character of the primemoverdoes not enterdirectlythe present invention, a-detailed descriptionds. hereunnecessary. Themotor A drives through a flexible coupli I2.' hecompressoriB- The compressor Bmay :be of any suitable ty e orconstruction. Since the specific formw em,-,

ployeddoes-not enter-into th inventionherein The pipes 13 and I4 areconnected by a T-fitting: l5. To. the upper end of T-fitting I5 issecured a flexible hose [6. The air valve His a well known structure,employed with practically all air compressors commonly known as anunloads: ingvalves.

The coupling connecting hose I6 to T-fitting;

15 maybe provided with a ball-check valveilfia, as shown; inFig. 4.

The governor D, may be of any suitabletypeon construction. While in theillustration ,giveI.1:.; I

have shown arspecific form of .hvdr ulicgovemorr it will bemnderstoodthat any type of governor which employs a-speed setting control shaftand;

an actuating-arm:forpontrolling the prime movermaybe employed.

Th general type. of hydraulic governor-illuse trated in the :drawingiswell known in the art. The governor is equipped with a'driven shaft I8,

which is connected through shaft .19 to a driven member of 'the motorinprime 'moverA. The governor controls the prime mover A by means of anactuating arm 20 which is in the form of "a plunger, beingdriveninwardly when the feed of fuel, pressure fluid or other motive-fluid tothe prim mover-is to bereduced and being pressed outwardly-when the sameis to be increased; In" the specificillustrationgiven, the plungerliiisa' partof a fluid driven 'servomotor and-it is connected through thelink 2| to a bell crank 22,-th'ebell crank being pivoted at 23upona-bracket arm I 24 secured to the-bottom of the governor A. The

outerarm of bellcrank 22 is secured, through rod: '25'to asecondbel-lcrank 26, pivoted upon the prime mover at 21, as shown best in Fig. 3.The bell crank 26 is connected through rod 28 to a third bell crank 29,pivoted at 30 upon the prime mover. Another connecting rod 3| joinscrank 29 to a lever arm 32 fixed to the throttle valve or fuelvalve-control shaft In. With the structure described, operation of thservomotor plunger 23 serves to control the throttle valve Ill.

The linkage E, in addition to the connections already described betweenthe plunger 20 and the throttle valve ID, provides means for changingthe speed setting control shaft 33 of the governor. The speed settingcontrol shaft 33 is present in practically all governors and provides ameans for adjusting the spring or other means of control through which apre-determined speed setting is obtained. Since the specific form of thespeed setting control mechanism is not a part of this invention, adetailed description is believed unnecessary. The specific form of speedsetting control in the governor A shown herein is set out in greatdetail in my copending application for Governor Mechanism, Serial No.655,086, filed March 18, 1946, now U. S. Patent No. 2,571,842.

In the illustration given, the rotatable speed setting control shaft 33is fixed to a collar 34 integrally formed with the control arm 35. Thecontrol arm 35 is pivotally secured to a rod 36 which is equipped at itsinner end with a piston 31. The piston 31 is mounted within a cylinder38. The opposite end of the cylinder 38 is connected by means of thethreaded rod 39 to the upper end of the bell crank 26. A spring 40 isinterposed between the piston 31 and the outer end of the cylinder 38.The flexible conduit l communicates with cylinder 38 on the inner sideof piston 31, as shown more clearly in Fig. 2.

Operation Assuming that it is desired to operate the prime mover, by wayof example at 400 R. P. M. minimum and 1200 R. P. M. maximum, thelinkage E is so arranged as to give 400 R. P. M. when the tank pressureis 150 p. s. i. (assumed maximum), and 1200 R. P. M. when the tankpressure is 100 p. s. i. (assumed minimum operating pressure).

Assuming that the pressure is zero p. s. i. in

the pressure tank C, in starting, the governor will operate the primemover at 1200 R. P. M. (maximum speed setting) until we reach 100 p. s.i. pressure in the tank. At this point, the governor speed adjusting arm35 is against the high speed stop 42 and spring 40 is compressed. Above100 p. s. i., the torque required to operate the compressor will loadthe prime mover and the plunger will move out the swinging bell crank22, rod 25, crank 26, rod 28, crank 29, rod 3|, and valve lever 32 so asto increase the flow of fuel to the prime mover. At the same time, theoutward movement of crank 26 draws rod 36 outwardly and swings arm andthe speed setting control shaft 33 in a counter-clockwise direction.This movement of the shaft 33 lowers the speed setting of the governor.This operation will continue until the maximum pressure of 150 p. s. i.in the tank has been reached and the prime mover is running at 400 R. P.M.

When the maximum pressure has been reached, the air valve l1, which isset to operate at 150 p. s. i., will function, as it does in commonpractice with air compressors, to cause the compressor to cease pumping.The release of pressure in line 13 would thereupon cause the piston 31to return to its quiescent position against stop 44 but for the actionof valve l Ba in holding the air trapped within cylinder 38. Valve Iliaholds the air for a substantial period before it can leak from cylinder38 and the linkage E is thus able only slowly to extend its length underthe urging of spring 40. This results in the prime mover increasingspeed very gradually rather than abruptly as in conventionalarrangements.

I provide a governor pull back spring 4! as indicated in Fig. 3. In aspecific example, the spring had a force of about 24 pounds. The size ofpiston 31 was such that with the air pressure used, I could obtain abouta 12-pound force. The spring 40 in the cylinder 38 operating the piston31 exerted about 6 pounds force (more force than was necessary tooperate the speed adjusting arm 35) I provide a high speed stop 42 whichengages the speed adjusting arm 35 in the starting up operation. Whenthe prime mover is initially started, spring 41 overrides spring 40 andcompresses it, forcing arm 35 clockwise against stop 42.

As the load increases, the servo 20 comes out and. spring 40 lengthensuntil at p. s. i., the piston 31 is held against stop 44 formed by ashoulder in the bore of cylinder 38. Above 100 p. s. i., as the servo 20comes out due to load, the link 35 pulls the arm 35 away from the highspeed stop and slows the prime mover down until at maximum p. s. i.) itis running at minimum speed and the arm 35 is against the low speed stop43. At this time valve [1 functions and the load is removed from theprime mover. Piston 31 is forced in by the compressed air admittedthrough channel Hi. This holds arm 35 against the low speed stop 43 andthe pull back spring 4| forces the servo in. holding the prime mover atidling speed.

When the pressure again drops below 150 p. s. i. (determined by airvalve differential), the compressor becomes operative again forsupplying pressure fluid to the tank C. In the meantime, linkage Elengthens and the operation of the prime mover again moves thecompressor under load.

The new structure eliminates the continual cutting in and out of the aircompressor as is now common. Within the range of the compressor, thereis a considerable speed change which would handle the various differentamounts of air being used.

Upon the operation of the valve device II which lifts the load of thecompressor from the prime mover, the prime mover at once starts to wardits maximum R. P. M. of 1200 and would maintain this high speed were itnot for the effective control provided through the cylinder 33 whichimmediately shortens the linkage E and changes the speed setting shaft33 so that the prime mover will, instead of racing at its maximum speed,operate at 400 R. P. M. (its minimum speed) While in the foregoingdescription, I have set forth a specific embodiment in considerabledetail, it will be understood that such details may be modified widelyby those skilled in the art without departing from the spirit of myinvention.

I claim:

1. In combination, a prime mover provided with a speed-varying lever, anair compressor driven thereby, a pressure tank, conduit means includingan unloading valve coupling the. compressor to the tank, a hydraulicgovernor coupled to the prime mover and provided with a speed-settingmember and a control shaft for regulating the speed of the prime mover,linkage coupling the control shaft to the speed-varying lever of theprime mover, connecting linkage coupling said first-mentioned linkage tothe speedsetting member operative to change the speed setting of thegovernor when the first-mentioned linkage is moved, said connectinglinkage being provided with an expansible coupling whereby its over-alllength can be varied, and a second conduit means connected to the outputof said compressor and operative to vary the length of said connectinglinkage responsively to the pressure generated by said compressor.

2. Apparatus according to claim 1 wherein said expansible couplingcomprises a cylinder rigidly afiixed to one side of the connectinglinkage and a spring-biased piston reciprocable therein, said pistonbeing provided with a piston rod connected to the other side of saidconnecting linkage.

3. Apparatus according to claim 1 wherein said second conduit means isprovided with a check valve tending to hold for a period of time thepressure in said conduit means at the maximum value attained by saidcompressor 4. Apparatus according to claim 1 wherein said expansiblecoupling comprises a, cylinder rigidly affixed to one side of theconnecting linkage and a spring-biased piston reciprocable therein, saidpiston being provided with a piston rod connected to the other side ofsaid connecting linkage, and wherein said second conduit means isprovided with a check valve tending to hold for a period of time thepressure in said second conduit means at the maximum value attained bysaid compressor, said pressure being operative to change the effectivelength of the connecting linkage in a direction tending to slow down theprime mover.

JOSEPH S. DALE,

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,550,875 Carpenter Aug. 25, 19251,550,876 Carpenter Aug. 25, 1925 2,137,219 Aikman Nov. 22, 19382,171,285 Baker Aug. 29, 1939 2,178,660 Carpenter Nov. 7, 1939 2,212,631Baker Aug. 27, 1940

